Question | Answer |
Describe the gram stain morphology Campylobacter jejuni | Curved(spirals or “seagulls”) gram negative bacilli |
Describe the gram stain morphology of Helicobacter pylori | Curved microaerophilic gram neg rods |
Describe the gram stain morphology of Haemophilus influenzae | Small gram negative coccobacilli |
Describe the gram stain morphology of Vibrio cholerae | Gram-negative, curved rods with polar flagella |
Describe the satellite effect | Tiny colonies of Haemophilus spp. growing on sheep blood agar very close to colonies of bacteria that can produce V factor |
Which factors are involved in the sattellite effect? | Hemin (X factor) and NAD (V factor) |
Why would a candle jar be necessary for cultivation of Haemophilus? | Because growth is stimulated by 5% to 10-% CO2. |
Beta hemolysis in Haemophilus spp. is best determined on which agar? | Rabbit or horse blood agars. |
What are the optimal conditions for the cultivation of C.jejuni? | Modified Skirrow's media: Columbia blood agar base, 7% horse-lysed blood and antibiotics (Vancomycin, trimethoprim, and polymyxin B) at 42 degrees C under microaerophilic conditions for 72 hours |
Describe a direct detection method for H. pylori: | The urea breath test is based on the fact that H.pylori breaks down urea in the stomach and it can be detected in the breath. Urea normally is produced by the body from excess or "waste" nitrogen-containing chemicals and then eliminated in the urine. |
Describe another direction method for H pylori | A biopsy of mucosa is taken from the stomach, and is placed into a medium containing urea and an indicator such as phenol red. The urease produced by H. pylori hydrolyzes urea to ammonia, increased ph changes the color of the specimen. (CLO test) |